At first, they were only at the station on odd days but now they are monitoring train travel 24 hours a day.

But their presence and image - they dress in long dark coats - provoked criticism from some passengers.

Some say they look like nightclub bouncers and one man lodged a complaint, claiming the staff had intimidated a passenger.

However, the officers say the public have got the wrong idea.

Steve Sweeting, senior revenue protection officer, said: "It is a shock to people, because they have not had their tickets checked at Huddersfield for 10 years.

"It is not just about trying to catch people out. We provide customer services as well. We carry bags and provide information for customers."

Mr Sweeting said the officers understand that some people have a genuine reason for having no ticket.

He said: "We know not everyone is a fare-dodger.

"We would love it if everyone was ticketed but unfortunately that doesn't happen. If people have not been able to buy a ticket before getting on the train, they can get one from the station when they get off."

If passengers have no ticket, the officers will not fine them but will ask them to buy a ticket and will check it.

Steve Johnson, safety and service quality manager, said the revenue officers have benefitted the station.

He said: "They have stopped undesirables coming to the station. Vandalism has also gone down.I think people now are also getting used to the idea that they will get their tickets checked and our revenue has increased."

Speaking about their image, he said: "Some people say they are like bouncers. But their coats are corporate issue. They are winter overcoats. The purpose is not to intimidate, it just gets very cold for them."

He added that all the officers had undergone intensive customer care courses.

He said the officers are here to stay and Transpennine Express is considering introducing manned barriers or turnstiles .

He said: "All the revenue from tickets just doesn't come to us. We collect for other companies on this line, like Arriva.

"We have a commitment to collect a certain amount of revenue and once we've hit our profit margin, 75% of the rest goes back to the industry."

Mr Johnson said ticket sales were also vital to Transpennine Express's plans to improve all its train stations.

Huddersfield will be one of the first stations to benefit next year fom new seats, information screens, announcing equipment, CCTV and interactive information points.